1. Field of the Invention
This invention relates to a roller belt sander, particularly to one installed with adjustment devices that can quickly and precisely keep a roller positioned via an eccentric micro-adjustment to achieve a preferable grinding effect.
2. Description of the Prior Art
As shown in FIG. 1, a conventional roller belt sander 10 consists of a main body 11, a front belt sanding roller 12 and a rear belt sanding roller 13 set in the top of the main body 10, and a conveying table 14. A work to be sanded is put on the conveying table 14 and transferred underneath the front belt sanding roller 12 and the rear belt sanding roller 13 orderly. The rear belt sanding roller 13 is provided with a bearing base 131 at its two ends respectively fixed on the wall of the main body 10 and installed with an adjustment device 20 for adjusting the height of the rear belt sanding roller 13. The adjustment device 20 is composed of a base 21, sliding base 22, a shaft base 23, a knob 24 and a locking grip 25. The base 21 is fixed on a wall edge of the main body 10 corresponding to one end of the rear belt sanding roller 13, and the sliding base 22 has its one side connected with the rear belt sanding roller 13 and the other side slid to fit restrictively with the base 21. The shaft base 23 is positioned at a top edge of the base 21, the knob 24 is rotatable to link with the sliding base 22 so as to keep the rear belt sanding roller 13 moved up and down, and the locking grip 25 is able to be whirled to fix the sliding base 22 tightly on the base 21 so that the bearing base 131 may be fixed in the sliding base 22. Then the rear belt sanding roller 13 can be positioned at a most appropriate level to co-work with the front belt sanding roller 12 to achieve a preferable grinding. But, it takes some time for the knob 24 to rotate to adjust the height of the rear belt sanding roller 13 in order to move the sliding base 22 first. Moreover, the adjustment device 20 has too many elements to cause a complicated assembly and a high manufacturing cost.